Spin amplitudes and gauge-invariance: from PHOTOS Monte Carlo to QCD

by Zbigniew Was

Friday 19 Oct 2007, 14:00 → 15:00 Europe/Zurich

TH Theory Conference Room (CERN)

One of the necessary steps in construction of precise Monte Carlo algorithms for QED was detailed analysis of spin amplitudes and in particular its parts which could be obtained not only by direct calculations, but by the iteration, necessary for definition of Monte Carlo algorithms, as well. At first, we will collect properties of spin amplitudes, which were used for definiton of reduction procedures in KKMC Mote Carlo and iterative solution of PHOTOS. In the second part of the talk we will investigate, how gauge invariance can help to organize form of exact tree-level spin amplitudes for processes of white current attached to fermionic line and additional two gluons.